1. Field of the Invention
The present invention relates to a method for manufacturing a semiconductor device, particularly a slurry for the CMP (Chemical Mechanical Polishing) technology for forming a damascene wiring such as Al, Cu or W, which is mounted on a DRAM or a high-speed logic LSI, and to a method for manufacturing a semiconductor device using the CMP slurry.
2. Description of the Related Art
Nowadays, the CMP process is said to be a process absolutely required in the field of manufacturing an LSI. In the step of forming a wiring, it is very difficult to carry out the processing of a Cu layer or a metal layer having a thickness not smaller than 1 μm, particularly the processing of an Al layer, by the conventional RIE (Reactive Ion Etching) process. In other words, it is difficult nowadays to employ the conventional method for forming the wiring structure that is indispensable for next-generation LSIs.
In order to overcome the difficulties noted above, vigorous research is being carried out in an attempt to improve the buried (damascene) wiring process using CMP technology.
Nowadays, it is required to suppress the erosion as much as possible and to carry out a CMP process low in defects in CMP technology. This has been derived from the situation that the design rule of the wiring has become small. For example, the wiring width for the next generation of devices is about 0.1 μm, which is substantially equal to or smaller than the size of the conventional abrasive particle.
Since, for example, a scratch generated during the CMP process is dependent on the particle size, it is necessary to use abrasive particles as small as possible in order to suppress the scratches generated during the CMP process. Also, it is effective to use particles having a small particle size for suppressing erosion. To be more specific, it was attempted in the past to carry out the CMP process by using abrasive particles having a small primary particle diameter, which is not larger than 50 nm, and dispersed in the dispersion medium in the form of the primary particles so as not to form secondary aggregated particles having a diameter of 0.2 μm or more within the dispersion medium.
However, it is difficult to control the primary particle size of the abrasive particles in the case where the abrasive particles have a small diameter and to control the diameter of the secondary particles formed by aggregation of the primary abrasive particles. Even if it were possible to control the particle diameter, the controlled particle size fails to fit the surface state of the polishing pad used nowadays, resulting in failure to obtain a sufficiently high polishing rate.